Base load is the power industry name for the constant flow of electricity that is maintained on the electrical grid to serve normal demand for power on the system. Traditionally, base load power has been provided by large coal-fired power plants.
When solar and wind power projects are scattered and small, as they are in the US today, these projects are not capabable of providing the constant flow of new power into the grid that is required to meet base load needs.
Natural gas power plants have also been used in the past to meet peak demand only, because gas-powered plants can be scaled up or scaled back very quickly. Natural gas-fired “peaker” plants can be started from a cold start and can be producing a couple hundred megawatts of power in 15 minutes.
Because of their quick starts and flexibility, natural gas fired combined cycle turbines are a perfect fit for filling base load power needs between the more intermittent flows of wind and solar generators. An extensive wind and solar system integrated with natural gas generators can create sustained base load power.
The Europeans, who are now far ahead of the US in electrical power technologies, are now moving toward a critical mass of wind power and natural gas power generation that is beginning to provide base load power. Statements that coal-fired electricity is the only source of base load power has been proven to be an obsolete idea.
We in the US can only move in this direction with massive new investment in solar, wind and natural gas fired power plants. Continued investment in the current obsolete coal-fired power plants and transmitting power over hundreds of miles is only postponing the day when the US will have a safe, secure and stable electrical power grid.
Note also that the PJM engineers base their argument for PATH only on peak load needs, not the normal levels of base load power.